1. Field of the Invention
The present invention relates to a wire bonding method that connects a first bonding point and a second bonding point with a wire, and more particularly, to a wire looping method used in wire bonding.
2. Prior Art
In wire bonding, it is preferable to keep the shape of wire loop constant during the bonding process. In the currently employed method, a capillary is raised after the wire is connected to a first bonding point, and then a reverse action is performed so that the capillary is moved horizontally by a small amount away from the second bonding point. These movements are performed with a clamp, which holds the wire, kept open. The Japanese Patent Application Publication ("Kokai") Nos. 57-87143 and 63-42135 disclose these methods.
In these prior art, the reverse action is an action of wire moving away from the second bonding point, forming a wire loop between the first and second bonding points.
In this reverse action, the capillary moves horizontally. This action of the capillary, however, drags the wire, and a force greater than the force required to deform the wire is applied to the wire. This causes a damage to the neck part of the wire which is a part of the wire at the first bonding point.